工厂模式

工厂模式分为: 简单工厂，基本工厂，抽象工厂

简单工厂模式

用户给一个值，工厂返回相应的对象。

DEMO

public interface Milk {
    String getMilk();
}

public class MengNiu implements Milk {
    @Override
    public String getMilk() {
        return "蒙牛";
    }

}
public class YiLi implements Milk {
    @Override
    public String getMilk() {
        return "伊利";
    }

}

public class SimpleFactory {
    public Milk getMilk(String name){

        if ("mengniu".equals(name)){
            return new MengNiu();
        }
        if ("yili".equals(name)){
            return new YiLi();
        }

        if ("sanlu".equals(name)){
            return new SanLv();
        }
        return null;
    }
}

普通工厂模式

需要哪个自己new一个对应的工厂。

DEMO

public interface Factory {

    Milk getMilk();
}

public class MengNiuFactory implements Factory {

    @Override
    public Milk getMilk() {
        return new MengNiu();
    }

}
public class YiLiFactory implements Factory {
    @Override
    public Milk getMilk() {
        return new YiLi();
    }
}


public class FactoryTest {
    public static void main(String[] args){
            Factory factory=new YiLiFactory();
            factory.getMilk().getMilk();
    }
}

抽象工厂

抽象工厂，用户只需要自己选择即可。不用关心任何其他的。

DEMO

public abstract class AbstractFactory  {

    //可以执行一些所有工厂统一标准
    abstract Milk getYiLi();

    abstract Milk getSanLu();

    abstract Milk getMengNiu();

}

public class MilkFactory extends AbstractFactory {


    Milk getYiLi(){
        return new YiLiFactory().getMilk();
    }

    Milk getSanLu(){
        //这里都可以直接new SanLu();
        return new SanLuFactory().getMilk();
    }

    Milk getMengNiu(){

        return new MengNiuFactory().getMilk();
    }
}